Bollettino valanghe

South Rockies

Mar 13 – 14, 2015Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 12 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Weather models are having trouble with the specifics of this weekend's weather. Any time it is raining, snowing or blowing, assume elevated avalanche danger.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–3
    Areas of wind slab may be encountered near ridge top.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–3
    Rain is expected to weaken an already moist snowpack, and may drive a loose wet or wet slab avalanche cycle.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    3–6
    We have concerns about this problem "waking up" with warm temperatures. A crust that previously isolated deep weaknesses has broken down with warming. Recent whumpfing indicates unstable snow.

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Two pulses of precipitation are expected this weekend. The first, on Saturday, brings 5-15 mm rain with strong to gale SW winds and a freezing level near 2400 m. Late on Sunday and into Monday, it looks more hopeful for snow (10-15 cm) with the freezing level closer to 1200 m. Winds switch briefly to the NW before swinging back to the SW. Weather models are not handling the developing situation well, so I have little confidence in the specifics of the weather forecast.

Avalanche Summary

On Tuesday, our field team members in the north Elk Valley experienced several whumpfs on south facing treed terrain at 2200 m. They also experienced a whumpf of a hard slab near ridge top at 2450 m and saw a deep slab release on a sunny aspect that probably occurred some time in the last week. Recent loose wet avalanches up to size 1.5 appeared to have been triggered by solar warming. On Sunday, a skier-triggered slab released on a weak layer near the ground in Kananaskis Country. Rain, snow and wind forecast for the weekend are likely to drive natural avalanche activity.

Snowpack Summary

Rain is likely to weaken the snowpack below about 2000 m on Saturday, and may cause a natural cycle of loose wet or wet slab avalanches. At low elevations, thin snowpack areas may simply melt. On the highest peaks, new snow will probably be shifted by strong winds into slabs lee to the SW. Cornices may develop. The most prominent snowpack feature is a thick crust 10-30cm below the surface, extending up to around 2200m elevation. The support of this crust is breaking down in response to warm temperatures. Persistent weak layers below this crust still react in snowpack tests and could wake up with continued warming or loading.

Regioni coperte